1. Field of the Invention
The present invention relates to a soundproof door, and more particularly, to an improved soundproof door having an STC number greater than of STC 30 determined in accordance with ASTM E413-10 and E90-09.
2. Description of Related Art
A soundproof door is a door which has been designed or retrofitted to cut out as much external noise as possible.
However, most soundproof doors currently used in prior art are wooden doors or synthesized plastic doors, those doors are poor in sound isolation or acoustic insulation.